Mechanical cleaning valve construction

Claim 1

IN A VALVE ASSEMBLY COMPRISING A VALVE BODY HAVING A VALVE SEAT, A VALVE RIGIDLY CONNECTED TO A ROTATABLY MOUNTED VALVE STEM FOR MOVING SAID VALVE TO AND FROM REGISTRATION WITH SAID VALVE SEAT, A MOTOR FOR ROTATING THE SAID VALVE STEM TO EFFECT THE SAID MOVEMENT OF SAID VALVE, MEANS FOR SHUTTING OFF SAID MOTOR IN RESPONSE TO A PREDETERMINED INCREASED TORQUE ON THE SAID MOTOR, A SLEEVE FORMING A PISTON THREADEDLY ENGAGED WITH SAID VALVE STEM AND MOUNTED AGAINST ROTATION FOR RELATIVE MOVEMENT BETWEEN SAID STEM AND SAID PISTON UPON REGISTRATION OF SAID VALVE WITH SAID VALVE SEAT, A STOP ENGAGEABLE BY THE SAID PISTON FOR ARRESTING MOVEMENT OF SAID PISTON AWAY FROM SAID VALVE WHILE SAID VALVE ROTATES AGAINST SAID VALVE SEAT, WHEREBY FURTHER ROTATION OF THE VALVE AGAINST THE VALVE SEAT EFFECTS AN INCREASED TORQUE ON SAID MOTOR SUFFICIENT TO SHUT OFF SAME, A CYLINDER ACCOMMODATING SAID PISTON AND HAVING A COMPRESSED FLUID TO BIAS SAID PISTON DOWNWARDLY RELATIVE TO SAID CYLINDER AND TO EXERT PRESSURE ON SAID VALVE THROUGH SAID PISTON AND SAID VALVE STEM DURING ROTATION OF THE SAID VALVE AGAINST THE SAID VALVE SEAT.